The present invention relates to the employment of trivalent silver (Ag[III]) compounds as bactericidal and algicidal agents in water treatment. Water soluble trivalent silver compounds are part of the class of multivalent silver compounds which have been the subject of patents granted to the instant inventor for water treatment. To date five such patents have been granted, namely, U.S. Pat. Nos. 5,017,295; 5,073,382; 5,078,902; 5,089,275; and 5,098,582. These patents all deal with divalent silver compounds and compositions that are anti-pathogenic but more particularly with (respectively) soluble complexes, alkaline pH stable compositions, halides, solid stabilized complexes and solid black oxide. All of said compounds more particularly related to treating utilitarian bodies of water defined as bodies of water having an ultimate use such as swimming pools, hot tubs, industrial cooling towers and municipal reservoirs where pathogens are known to proliferate. While all of the cited patents describe multivalent silver compounds which have many novel advantages in treating said bodies of water and while they all conform to regulatory requirements for treating said bodies of water, such as the rules and regulations of the Environmental Protection Agency for treating swimming pools, none of the above inventions provides for an antipathogenic composition which embodies all of the following characteristics:
1. A liquid composition;
2. Not precipitated out by halides present in the water treated;
3. Non-staining in concentrated form to human skin and to the surfaces of the containing vessel of said bodies of water.
None of the previously patented compounds or compositions met all of these three criteria, despite the fact that each invention embodied unique compositions of Ag(II) moieties. The first patent, for example, in its preferred embodiments dealing with Ag(II) complexes, though of liquid composition, stained the skin in concentrated form and precipitated cupious white material when introduced into saline bodies of water. While of all the previous patents the silver halides were free of this nuisance and were nonstaining, they all were solid compositions which were totally insoluble in water. Accordingly, a composition meeting these three criteria was sought. Therefore, attempts were made to synthesize water soluble Ag(III) compounds, and testing and evaluation of their efficacy to see whether they met all the aforementioned criteria. The Ag(II) compositions were all light stable and it was verified as anticipated for Ag(III) as well. Accordingly, the tests and evaluations proved successful which has led to the final development of this invention, namely, trivalent silver compositions capable of killing and/or preventing the replication of gram positive and gram negative bacteria, as well as algae in utilitarian water bodies, such as swimming pools, which can be supplied in liquid concentrate form which will not stain the skin nor precipitate in the presence of halides.
In the course of the testing of the compositions of this invention, another previously unanticipated advantage of these compositions became evident. Whereas all the previous Ag(II) compositions required additions of oxidizing agents, such as alkali metal persulfates, to synergize their efficacy, these compositions required no such additions and were efficacious in themselves.